As Infection is a leading cause of morbidity and mortality in cancer patients with severe granulocytopenia and other damage to host defenses, this project was designed to detect the presence of infectious agents in these patients prior to and during infection to provide a sound base for antibiotic therapy. It is also designed to detect carriers and/or "shedders" of potential pathogens or highly resistant strains so that they can be isolated from the high risk patients. In addition it affords microbiological data for a number of protocols which involve infection in cancer patients. To provide such data all patient samples are studied intensively and all of the microorganisms recovered are identified as to genus and species. Surveillance cultures taken from high risk patients provide data on patient flora at admission and subsequent acquisition during the hospital stay to alert the physician to their presence and antibiotic susceptibility prior to infection.